replacing dovetail ways with THK linear bearing

[wisp]

I have searched, but can not find if anyone has machined away the dovetail ways on there mini/micro mill, or lathe for that matter, and mounted liner bearings in their place?
I was thinking of machining the dovelails off, and just leaving a nice square shoulder for the linear bearing to push against. I was not going to machine the ground surface that the rails would actually mount to, since it is already very flat. Just drill and tap hole along it for the rail.

I also have some crossed roller bearings that might make a really good dovetail replacement.

thoughts?

[CerveloRod]

Haven't done it but have thought of it.

I was thinking of buying a new piece of steel plate to use, maybe 1.5" thick and mounting the rails onto the flat bottom of the saddle for my mini-mill. I would have also put a spacer in the mill-head so you could get +/- 5" of travel out of it, right now I just barely get 4" envelope.

After I spent about 4 hours with some dykem and polish I'm glad I didn't go to the effort to change to rails.

If I was to build a mill from the ground up I would use rails, as I will with my small router project...

Rod

[wizard]

A long while ago I worked on small lathes that we considred doing the above on. For a number of reasons we never did.

For one thing the project is bigger than it first appears as alignment changes on a number of thins requiring fabrication of parts. Another issue is stiffness of the system afterward. We spcfically looked into crossed roller ways as these had the lowest hieght change of the technologies looked at.

To address wear on one series of lathes, we had the ways rebuilt by a professional machine tool builder. He made use of Teracite I believe. Plus he made some other modifications. This worked out very well.

For a mill I wouldn't bother unless you can determine that you have plenty of room for larger slides. That is slides that can handle the load and are mechanically stiff.

Dave